1. Field of the Invention
The present invention relates to a capped or sealed rolling bearing, and more particularly, it relates to an improvement in sealed portions between sealing plates and a rotating race of a rolling bearing.
2. Related Background Art
In a conventional capped rolling bearing for example as disclosed in the Utility Model application Laid-open No. 62-85723, as shown in FIGS. 3 and 4, sealing plate receiving grooves 72 having appropriate shapes are formed in both edge portions of an inner peripheral surface of an outer race 70, and sealing plate receiving grooves 76 each having a U-shaped cross-section for slidably receiving sealing plate 80 are also formed in both edge portions of an outer peripheral surface of an inner race 74. Each sealing plate 80 comprises a metallic core 82 and a rubber seal 84 integrally fixed to the metallic core, which rubber seal 84 is provided at its outer periphery with a thickened attachment portion 86 to be fixed to the outer race 74 and is also provided at its inner periphery with an outer and inner lips 88 and 90 which extend obliquely in different directions. Each sealing plate can be arranged between the inner and outer races in such a manner that the attachment of fixing portion 86 of the sealing plate is fixedly fitted into the fixing groove 72 of the outer race, and the outer lip 88 is slidably abutted against an outer peripheral surface 94 contiguous to the slide groove 76 of the inner race and at the same time the inner lip 90 is slidably abutted against a vertical surface 92 of the inner race.
With this arrangment, since the two lips 88 and 90 have a common thinned portion or neck portion 96, these lips can be deformed integrally around the neck portion, whereby even if one of the lips 88 or 90 is worn to decrease its contact pressure against the surface 94 or 92, the contact pressure of the other lip 90 or 88 increases to compensate the reduction in the sealing ability of the one lip.
However, since the inner lip 90 is thicker and has greater rigidity with the result that it is difficult for the inner lip to deform in response to the movement of the bearing, (relative axial movement between the inner race and the outer race), the contact pressure of the inner lip 90 against the vertical surface 92 will inevitably increase, thus increasing a torque required for relatively rotating the inner and outer races.